Slider Widget 2.8.1

A slider with two thumbs, one that represents the min value and
the other the max. Actually a composition of two sliders, both with
the same background. The constraints for each slider are adjusted
dynamically so that the min value of the max slider is equal or greater
to the current value of the min slider, and the max value of the min
slider is the current value of the max slider.
Constructor assumes both thumbs are positioned absolutely at the 0 mark on
the background.